Carbohytrades are also called sucharids or sugars. The GI (glycemic index) says how fast a carbohydrate is absorbed by the body. The Carbohydrate with the highest GI is sugar like we heve in in sweets or put it into our caffee. In General most carbohydrates are good and fast energy sources. One gram of carbohydrate has 4 kilocalories. (same as protein) Fats have much more energy (9 Kcal / gram).